IssueTracker

Yigit, do you have time to fix it?

reemission of the same liveData is racy

yea i'll take it.

Thanks for the detailed analysis. This may not be an issue anymore since we've started using Main.immediate there but I' not sure; I'll try to create a test case.

just emitting same live data reproduces the issue.

    @Test
    fun raceTest() {
        val subLiveData = MutableLiveData(1)
        val subject = liveData(testScope.coroutineContext) {
            emitSource(subLiveData)
            emitSource(subLiveData) //crashes
        }
        subject.addObserver().apply {
            testScope.advanceUntilIdle()
        }
    }

With 2.2.0-alpha04 (that use Main.immediate), the issue seems to be still there (I tested it by calling emitSource() twice, like your test case)

yea sorry immediate does not fix it.
I actually have a WIP fix for it:
https://android-review.googlesource.com/c/platform/frameworks/support/+/1112186

if your case is the one i found (emitting same LiveData multiple times, as shown in #5) you can work around it by adding a dummy transformation.


val subLiveData = MutableLiveData(1)
        val subject = liveData(testScope.coroutineContext) {
            emitSource(subLiveData.map {it })
            emitSource(subLiveData.map {it} )
        }

Project: platform/frameworks/support
Branch: androidx-master-dev

commit af12e75e6b4110f48e44ca121466943909de8f06
Author: Yigit Boyar <yboyar@google.com>
Date:   Tue Sep 03 12:58:11 2019

    Fix coroutine livedata race condition
   
    This CL fixes a bug in liveData builder where emitting same
    LiveData source twice would make it crash because the second
    emission registry could possibly happen before first one is
    removed as source.
   
    We fix it by using a suspending dispose function. It does feel
    a bit hacky but we cannot make DisposableHandle.dispose async
    and we do not want to block there. This does not mean that there
    is a problem if developer disposes it manually since our emit
    functions take care of making sure it disposes (and there is
    no other way to add source to the underlying MediatorLiveData)
   
    Bug: 140249349
    Test: BuildLiveDataTest#raceTest_*
   
    Change-Id: I0b464c242a583da4669af195cf2504e2adc4de40

M       lifecycle/lifecycle-livedata-ktx/api/2.2.0-alpha05.txt
M       lifecycle/lifecycle-livedata-ktx/api/current.txt
M       lifecycle/lifecycle-livedata-ktx/api/public_plus_experimental_2.2.0-alpha05.txt
M       lifecycle/lifecycle-livedata-ktx/api/public_plus_experimental_current.txt
M       lifecycle/lifecycle-livedata-ktx/api/restricted_2.2.0-alpha05.txt
M       lifecycle/lifecycle-livedata-ktx/api/restricted_current.txt
M       lifecycle/lifecycle-livedata-ktx/src/main/java/androidx/lifecycle/CoroutineLiveData.kt
M       lifecycle/lifecycle-livedata-ktx/src/test/java/androidx/lifecycle/BuildLiveDataTest.kt

https://android-review.googlesource.com/1112186
https://goto.google.com/android-sha1/af12e75e6b4110f48e44ca121466943909de8f06

Project: platform/frameworks/support
Branch: androidx-main

commit 0a9efa914d322810f8dc8d9ba06e79d164c8892d
Author: Jeremy Woods <jbwoods@google.com>
Date:   Wed Jun 09 13:01:36 2021

    Fix lint crashes on kotlin top level properties
   
    We need to handle cases where kotlin functions don't have a surrounding
    class.
   
    This change allows the surrounding class to be null and in that case we
    just skip the check.
   
    RelNote: "The `OnCreateDialogIncorrectCallback` lint check will no
    longer crash when declaring a top level variable."
    Test: kotlin anonymous object test
    Bug: 189967522
   
    Change-Id: I62de88c344cee0cb9deda26c9e5fc27247cf2d95

M       fragment/fragment-lint/src/main/java/androidx/fragment/lint/OnCreateDialogIncorrectCallbackDetector.kt
M       fragment/fragment-lint/src/test/java/androidx/fragment/lint/OnCreateDialogIncorrectCallbackDetectorTest.kt

https://android-review.googlesource.com/1731936

Hello I am getting the same error probably after updating AGP version

```

../../src/main/java/com/sample/app/App.kt: Unexpected failure during lint analysis of App.kt (this is a bug in lint or one of the libraries it depends on)

Message: class androidx.fragment.lint.OnCreateDialogIncorrectCallbackDetector$UastHandler tried to access protected method 'org.jetbrains.kotlin.psi.KtClassOrObject org.jetbrains.uast.kotlin.KotlinUClass.getKtClass()' (androidx.fragment.lint.OnCreateDialogIncorrectCallbackDetector$UastHandler is in unnamed module of loader com.intellij.util.lang.UrlClassLoader @10f53730; org.jetbrains.uast.kotlin.KotlinUClass is in unnamed module of loader java.net.URLClassLoader @4489af75)

The crash seems to involve the detector androidx.fragment.lint.OnCreateDialogIncorrectCallbackDetector.
You can try disabling it with something like this:
    android {
        lint {
            disable "DialogFragmentCallbacksDetector"
        }
    }

Stack: IllegalAccessError:OnCreateDialogIncorrectCallbackDetector$UastHandler.visitClass(OnCreateDialogIncorrectCallbackDetector.kt:78)
←UElementVisitor$DispatchPsiVisitor.visitClass(UElementVisitor.kt:553)
←UElementVisitor$DelegatingPsiVisitor.visitClass(UElementVisitor.kt:1162)
←AbstractKotlinUClass.accept(AbstractKotlinUClass.kt:43)
←ImplementationUtilsKt.acceptList(implementationUtils.kt:29)
```

AGP 7.4.0-alpha03
Kotlin 1.6.20-M1

This is weird as the App.kt is a DaggerApplication and does not have any DialogFragment in it

It got fix after updating androidx related dependency to 2.5.0-rc01

Sorry I am still getting the same error in the CI CD pipelines but not in local machine, any idea?